- Time limit: 1.00 s
- Memory limit: 512 MB
Each square of an 8 \times 8 chessboard has a robot. Each robot independently moves k steps, and there can be many robots on the same square.
On each turn, a robot moves one step left, right, up or down, but not outside the board. It randomly chooses a direction among those where it can move.
Your task is to calculate the expected number of empty squares after k turns.
The only input line has an integer k.
Print the expected number of empty squares rounded to six decimal places (rounding half to even).
- 1 \le k \le 100